Video shows a Boston terror suspect falling to the ground after being shot. (WBZ-TV)

The blurry video shows six plainclothes officers surrounding him before opening fire.

“I think that District Attorney (Daniel) Conley is making the right call getting this information out there to the public very quickly,” Davis said. “I was also struck by the fact that the officers, after taking a tactical stance and you can tell there is a problem here just the way they have lined up (and) they have done things exactly the way we have trained them…they cite the weapon, they draw the weapon and they start taking half-steps backwards…gave the suspect an enormous amount of latitude in movement.

“…This situation dragged out for a distance a lot longer than I expected. He had ample opportunity to follow their commands and drop the knife.”

Davis says that the Boston Police Department has “set a precedent” by releasing the Roslindale shooting video.

“People across the country are demanding it, police across the United States are putting video cameras on themselves and I think you’ll see this play out quite a bit,” he added.